Airlines very frequently get banned from US airspace because their procedures do not meet the strict safety bar set by the FAA. So it’s very reasonable to assume that what was identified as a training gap on the MCAS operations was due to sloppy regional airline training procedures.

So it’s true that it would have been taken more seriously in the US, but it’s because the FAA and NTSB set the bar for aviation safety and crash investigation rigor world wide.